After reading all the comments I went into the shed and got out my metal/pipe detector. Found out the battery connector was broke so spent £10 on a new one.

Tested it out on my binders and other bits. Went to the co op and got readings on 2 of them. Did not try the ones with the satchel bag though.

Got them home and opened them like it was Christmas morning and was gutted to find no card.

I have been to loads of the big supermarkets and even Southampton hospital to find all the tops have been neatly cut open. I have looked at least 25-30 packs. I might have had a shake of them but I am not that low. They even left the packet and the Rooney card in there though!!!

I have had the same thing, got a reading on a binder but it didn't have a card inside. I have also found loads with neatly cut open outer bags, with the LE and free pack of cards left in. I wonder how people are getting away with this as the binders are always pretty near or visible from the tills.